Electrical connector and method for manufacturing an electrical connector

ABSTRACT

An electrical connector for detachably connecting an electrical lead to an implantable medical device includes a conductive housing and a plurality of spring contacts. The conductive housing extends from a proximal end to a distal end. The conductive housing has an interior surface forming a hollow cylinder. The plurality of spring contacts projects from the interior surface of the conductive housing and toward the proximal end. The plurality of spring contacts is at least partially contained within the conductive housing and configured to form an electrical connection to an electrical lead inserted within the conductive housing. The conductive housing and the plurality of spring contacts are integrally formed by an additive manufacturing process such that the electrical connector is a unitary structure.

TECHNICAL FIELD

The application is a continuation of U.S. application Ser. No.15/065,065, filed Mar. 9, 2016, which claims the benefit of priorityunder 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No.62/132,337, filed on Mar. 12, 2015, which is herein incorporated byreference in its entirety.

TECHNICAL FIELD

The present invention relates to electrical connectors and methods formanufacturing electrical connectors. More specifically, the inventionrelates to electrical connectors suitable for use with an implantablemedical device.

BACKGROUND

Implantable medical devices, such as implantable cardioverterdefibrillators, pacemakers, and neuromodulation devices, are used in avariety of therapeutic applications. In some applications, one or moreimplantable electrical leads are employed to deliver therapy from animplanted medical device to tissues within a body. The electrical leadmay have one or more electrodes near a distal end of the electrical leadelectrically connected to terminal pin contacts near a proximal, orterminal, end of the electrical lead. The terminal end of the electricallead may be inserted into ports in a lead connector block of theimplanted medical device. The lead connector block may include anelectrical connector that contacts a terminal pin contact of theelectrical lead to electrically connect the implanted medical device tothe electrical lead. The electrical connection is detachable so that theelectrical lead may be coupled and decoupled as necessary.

The electrical connectors within the lead connector block may includespring contacts to provide the electrical connection to the terminal pincontacts once the terminal end of the electrical lead is inserted intothe lead connector block. A minimum level of normal, or contact, forcemust be provided by the spring contacts to ensure a reliable electricalconnection between the electrical connector and the electrical lead.Flat, or leaf, spring contacts may be used, but such flat, or leaf,spring contacts may be overstressed or bent, particularly with repeatedcoupling and decoupling between the electrical lead and the leadconnector block, leading to a normal force that is lower than thatnecessary to provide a reliable electrical connection.

SUMMARY

In Example 1, an electrical connector for detachably connecting anelectrical lead to an implantable medical device includes a conductivehousing and a plurality of spring contacts. The conductive housingextends from a proximal end to a distal end and has an interior surfaceforming a hollow cylinder. The plurality of spring contacts projectsfrom the interior surface of the conductive housing and toward theproximal end. The plurality of spring contacts is at least partiallycontained within the conductive housing and configured to form anelectrical connection to an electrical lead inserted within theconductive housing. The conductive housing and the plurality of springcontacts are integrally formed by an additive manufacturing process suchthat the electrical connector is a unitary structure.

In Example 2, the electrical connector of Example 1, wherein the eachspring contact of the plurality of spring contacts has a lengthextending from the conductive housing to a tip of the spring contact,and an average cross-sectional aspect ratio along its length, whereinthe average cross-sectional aspect ratio is from 1 to 3.

In Example 3, the electrical connector of any of Examples 1-2, whereinthe average cross-sectional aspect ratio is 1.

In Example 4, the electrical connector of any of Examples 1-3, whereinthe additive manufacturing process is a powder bed fusion processemploying a metal powder, wherein the metal powder is an alloy includingabout 34 to 36 wt. % nickel, about 19 to 21 wt. % chromium, about 9 to11 wt. % molybdenum, and about 32 to 38 wt. % cobalt or consistingessentially of 34 to 36 wt. % nickel, 19 to 21 wt. % chromium, 9 to 11wt. % molybdenum, and 32 to 38 wt. % cobalt.

In Example 5, the electrical connector of any of Examples 1-4, whereineach spring contact of the plurality of spring contacts has a lengthextending from the conductive housing to a tip of the spring contact,and has an elliptical cross-sectional shape along at least a portion ofits length.

In Example 6, the electrical connector of any of Examples 1-5, whereinthe plurality of spring contacts includes at least twenty springcontacts.

In Example 7, the electrical connector of any of Examples 1-6, whereinthe conductive housing further includes a distal portion adjacent to thedistal end, and a proximal portion adjacent to the proximal end andspaced apart from the distal portion. The plurality of spring contactsprojects from the interior surface of the distal portion of theconductive housing and toward the proximal end. The proximal portion isconnected to the distal portion by the plurality of spring contacts.

In Example 8, the electrical connector of any of Examples 1-7, whereineach spring contact of the plurality of spring contacts is canted orspirals at least partially around an axis of the conductive housing.

In Example 9, an implantable medical device includes a case and a leadconnector block. The case includes operational circuity for providingtherapy and an electrical feedthrough electrically connected to thecircuit. The lead connector block is attached to the case at theelectrical feedthrough. The lead connector block is configured toreceive at least one terminal pin of an electrical lead. The leadconnector block includes an electrical connector according to any ofExamples 1-8 electrically connected to the electrical feedthrough fordetachably connecting the electrical lead to the operational circuitry.

In Example 10, a method for manufacturing an electrical connector fordetachably connecting an electrical lead to an implantable medicaldevice includes performing an additive manufacturing process to form anelectrical connector. The electrical connector includes a conductivehousing having an interior surface extending from a proximal end to adistal end forming a hollow cylinder. The electrical connector alsoincludes a plurality of spring contacts projecting from the interiorsurface of the conductive housing and toward the proximal end, theplurality of spring contacts at least partially contained within theconductive housing and configured to form an electrical connection to anelectrical lead inserted within the conductive housing. The conductivehousing and the plurality of spring contacts are integrally formed bythe additive manufacturing process such that the electrical connector isa unitary structure.

In Example 11, the method of Example 10, further comprising finishing atleast a portion of a surface of the electrical connector.

In Example 12, the method of Example 11, wherein finishing includes atleast one of electrochemical polishing, mechanical polishing, electroplasma polishing, glazing, wet blasting, grit blasting, wire electricaldischarge machining, and passivating techniques.

In Example 13, the method of any of Examples 10-12, wherein the additivemanufacturing process is a powder bed fusion process.

In Example 14, the method of Example 13, wherein the powder bed fusionprocess is a micro laser sintering process employing a metal powderhaving an average particle size of less than 10 micrometers.

In Example 15, the method of Example 14, wherein the metal powder has anaverage particle size of less than 5 micrometers.

In Example 16, the method of any of Examples 10-15, wherein the eachspring contact of the plurality of spring contacts has a lengthextending from the conductive housing to a tip of the spring contact,and an average cross-sectional aspect ratio along its length, whereinthe average cross-sectional aspect ratio is from 1 to 3.

In Example 17, the method of Example 16, wherein the averagecross-sectional aspect ratio is 1.

In Example 18, the method of any of Examples 10-17, wherein each springcontact of the plurality of spring contacts has a length extending fromthe conductive housing to a tip of the spring contact, and has anelliptical cross-sectional shape along at least a portion of its length.

In Example 19, the method of any of Examples 10-18, wherein theplurality of spring contacts includes at least twenty spring contacts.

In Example 20, the method of any of Examples 10-19, wherein each springcontact of the plurality of spring contacts is canted or spirals atleast partially around an axis of the conductive housing.

In Example 21, an electrical connector for detachably connecting anelectrical lead to an implantable medical device includes a conductivehousing and a plurality of spring contacts. The conductive housingextends from a proximal end to a distal end and has an interior surfaceforming a hollow cylinder. The plurality of spring contacts projectsfrom the interior surface of the conductive housing and toward theproximal end. The plurality of spring contacts is at least partiallycontained within the conductive housing and configured to form anelectrical connection to an electrical lead inserted within theconductive housing. The conductive housing and the plurality of springcontacts are integrally formed by an additive manufacturing process suchthat the electrical connector is a unitary structure.

In Example 22, the electrical connector of Example 21, wherein the eachspring contact of the plurality of spring contacts has a lengthextending from the conductive housing to a tip of the spring contact,and an average cross-sectional aspect ratio along its length, whereinthe average cross-sectional aspect ratio is about 1 to about 3.

In Example 23, the electrical connector of any of Examples 21-22,wherein the average cross-sectional aspect ratio is about 1.

In Example 24, the electrical connector of any of Examples 21-23,wherein the additive manufacturing process is a powder bed fusionprocess employing a metal powder, wherein the metal powder is an alloyincluding about 34 to 36 wt. % nickel, about 19 to 21 wt. % chromium,about 9 to 11 wt. % molybdenum, and about 32 to 38 wt. % cobalt.

In Example 25, the electrical connector of any of Examples 21-24,wherein each spring contact of the plurality of spring contacts has alength extending from the conductive housing to a tip of the springcontact, and has an elliptical cross-sectional shape along at least aportion of its length.

In Example 26, the electrical connector of any of Examples 21-24,wherein each spring contact of the plurality of spring contacts has alength extending from the conductive housing to a tip of the springcontact, and has a triangular cross-sectional shape along at least aportion of its length.

In Example 27, the electrical connector of any of Examples 21-26,wherein the plurality of spring contacts includes at least twenty springcontacts.

In Example 28, the electrical connector of any of Examples 21-27,wherein the conductive housing further includes a distal portionadjacent to the distal end, and a proximal portion adjacent to theproximal end and spaced apart from the distal portion. The plurality ofspring contacts projects from the interior surface of the distal portionof the conductive housing and toward the proximal end. The proximalportion is connected to the distal portion by the plurality of springcontacts.

In Example 29, the electrical connector of any of Examples 21-28,wherein each spring contact of the plurality of spring contacts iscanted or spirals at least partially around an axis of the conductivehousing.

In Example 30, a method for manufacturing an electrical connector fordetachably connecting an electrical lead to an implantable medicaldevice includes performing an additive manufacturing process to form anelectrical connector. The electrical connector includes a conductivehousing having an interior surface extending from a proximal end to adistal end forming a hollow cylinder. The electrical connector alsoincludes a plurality of spring contacts projecting from the interiorsurface of the conductive housing and toward the proximal end, theplurality of spring contacts at least partially contained within theconductive housing and configured to form an electrical connection to anelectrical lead inserted within the conductive housing. The conductivehousing and the plurality of spring contacts are integrally formed bythe additive manufacturing process such that the electrical connector isa unitary structure.

In Example 31, the method of Example 30, further comprising finishing atleast a portion of a surface of the electrical connector.

In Example 32, the method of Example 31, wherein finishing includes atleast one of electrochemical polishing, mechanical polishing, electroplasma polishing, glazing, wet blasting, grit blasting, wire electricaldischarge machining, and passivating techniques.

In Example 33, the method of any of Examples 30-32, wherein the additivemanufacturing process is a powder bed fusion process.

In Example 34, the method of Example 33, wherein the powder bed fusionprocess is a micro laser sintering process employing a metal powderhaving an average particle size of less than about 10 micrometers.

In Example 35, the method of Example 34, wherein the metal powder has anaverage particle size of about 5 micrometers.

In Example 36, an implantable medical device includes a case and a leadconnector block. The case includes operational circuity for providingtherapy, and an electrical feedthrough electrically connected to thecircuit. The lead connector block is attached to the case at theelectrical feedthrough. The lead connector block is configured toreceive at least one terminal pin of an electrical lead. The terminalpin includes at least one terminal pin contact. The lead connector blockincludes an electrical connector electrically connected to theelectrical feedthrough for detachably connecting the electrical lead tothe operational circuitry. The electrical connector includes aconductive housing and a plurality of spring contacts. The conductivehousing extends from a proximal end to a distal end and has an interiorsurface forming a hollow cylinder. The plurality of spring contactsprojects from the interior surface of the conductive housing and towardthe proximal end. The plurality of spring contacts is at least partiallycontained within the conductive housing and configured to form anelectrical connection to an electrical lead inserted within theconductive housing. The conductive housing and the plurality of springcontacts are integrally formed by an additive manufacturing process suchthat the electrical connector is a unitary structure.

In Example 37, the device of Example 36, wherein each spring contact ofthe plurality of spring contacts has a length extending from theconductive housing to a tip of the spring contact, and an averagecross-sectional aspect ratio along its length, wherein the averagecross-sectional aspect ratio is about 1 to about 3.

In Example 38, the device of any of Examples 36-37, wherein the additivemanufacturing process is a powder bed fusion process employing a metalpowder, wherein the metal powder is an alloy including about 34 to 36wt. % nickel, about 19 to 21 wt. % chromium, about 9 to 11 wt. %molybdenum, and about 32 to 38 wt. % cobalt.

In Example 39, the device of any of Examples 36-38, wherein each springcontact of the plurality of spring contacts has a length extending fromthe conductive housing to a tip of the spring contact, and has anelliptical cross-sectional shape along at least a portion of its length.

In Example 40, the device of any of Examples 36-39, wherein theplurality of spring contacts includes at least twenty spring contacts.

While multiple embodiments are disclosed, still other embodiments of thepresent invention will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the invention. Accordingly, the drawings anddetailed description are to be regarded as illustrative in nature andnot restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a medical system including an implantablemedical device including an electrical connector in accordance withembodiments of the present invention.

FIG. 2 is a schematic side view of a portion of the implantable medicaldevice of FIG. 1.

FIGS. 3A and 3B are a proximal end view and a cross-sectional view,respectively, of an electrical connector in accordance with embodimentsof the present invention.

FIGS. 4A and 4B are a proximal end view and a cross-sectional view,respectively, of the electrical connector shown in FIGS. 3A and 3B,illustrating contact between the electrical connector and a terminal pincontact of an implantable medical lead.

FIGS. 5A and 5B are a distal end view, and a cross-sectional view,respectively, of another electrical connector in accordance withembodiments of the present invention.

FIGS. 6A and 6B are a distal end view and a cross-sectional view,respectively, of another electrical connector in accordance withembodiments of the present invention.

FIGS. 7A and 7B are a distal end view and a cross-sectional view,respectively, of another electrical connector in accordance withembodiments of the present invention.

FIG. 8 is a schematic view of a system for additively manufacturingelectrical connectors in accordance with embodiments of the presentinvention.

While the invention is amenable to various modifications and alternativeforms, specific embodiments have been shown by way of example in thedrawings and are described in detail below. The intention, however, isnot to limit the invention to the particular embodiments described. Onthe contrary, the invention is intended to cover all modifications,equivalents, and alternatives falling within the scope of the inventionas defined by the appended claims.

DETAILED DESCRIPTION

FIG. 1 provides an illustrative, but non-limiting, example of a medicalapplication using an implantable medical device and an implantableelectrical lead electrically connected to the implantable medicaldevice. The application is illustrative only, as implantable medicaldevices incorporating embodiments of the present invention may be usedin a variety of medical applications and for a variety of purposes.

FIG. 1 is a schematic view of a medical system 10 including anelectrical connector in accordance with embodiments of the presentinvention. FIG. 1 shows that the medical system 10 may include animplantable medical device (IMD) 12 and at least one electrical lead 14.The IMD 12 may include a case 16 and a lead connector block 18. The case16 may include operational circuitry 20. In the embodiment of FIG. 1,two electrical leads 14 are illustrated, one shown coupled to the leadconnector block 18, and another shown decoupled to the lead connectorblock 18. Each of the electrical leads 14 may include a proximal orterminal end 22, a distal end 24, a first terminal contact 26, a secondterminal contact 28, a first electrode 30, and a second electrode 32. Inthe embodiment of FIG. 1, the first terminal contact 26 and the secondterminal contact 28 may both be located proximate to the proximal orterminal end 22. The first electrode 30 and the second electrode 32 mayboth be located proximate to the distal end 24 and be electricallyconnected to the first terminal contact 26 and the second terminalcontact 28, respectively, by conductors (not shown) running within eachof the electrical leads 14.

The first terminal contact 26 and the second terminal contact 28 of eachof electrical leads 14 may be coupled to the lead connector block 18 byan electrical connector embodiment within the lead connector block 18,as described below. Once coupled, the operational circuitry 20 withincase 16 may be electrically connected to the first terminal contact 26and the second terminal contact 28 of each of electrical leads 14. Soconnected, operational circuitry 20 may be configured to provide electrostimulation therapy in the form of electrical pulses delivered by atleast one of the first electrode 26 or the second electrode 28 of theelectrical leads 14. The operational circuitry 20 may also employ atleast one of the first electrode 26 or the second electrode 28 of theelectrical leads 14 to sense conditions within the body that indicatethe effectiveness of the therapy and/or indicate a need for additionaltherapy. The therapy may be in the form of electrical pulses, forexample, defibrillation, cardioversion, heart pacing, orneuromodulation.

In the embodiment of FIG. 1, the case 16 may be made of a biocompatibleconductor, such as titanium. Each of the electrical leads 14 may be madeof insulating material along most of its structure, for example,polyurethane or silicone. The insulating structure separates andisolates one or more terminal contacts, such as the first terminalcontact 26 and the second terminal contact 28, or electrodes, such asthe first electrode 30 and the second electrode 32, from each other. Inthe illustrated embodiment, the first electrode 30 is illustrated as aplate-type electrode and the second electrode 32 is illustrated as acoil electrode extending circumferentially about the electrical lead 14.However, it is understood that other electrode shapes, including flatplates and non-circumferentially extending electrodes, may be used. Thefirst terminal contact 26, the second terminal contact 28, the firstelectrode 30, and the second electrode 32 may also be made of abiocompatible conductor, such as titanium.

FIG. 2 is a schematic side view of a portion of the implantable medicaldevice 12 of FIG. 1. FIG. 2 shows a portion of the IMD 12 including aportion of the case 16 and the lead connector block 18. As shown in FIG.2, the case 16 may further include an electrical feedthrough 34providing a connection between the operational circuitry 20 and the leadconnector block 18. The lead connector block 18 may include at least oneterminal pin receiving port 36 (two shown), at least one firstelectrical connector 38 (two shown), at least one second electricalconnector 40, and a plurality of connecting wires 42. The terminal pinreceiving port 36 is an opening in the lead connector block 18 intowhich the proximal end 22 may be received when coupling the electricallead 14 to the lead connector block 18. The terminal pin receiving port36, the first electrical connector 38, and the second electricalconnector 40 may be axially aligned. Each of the first electricalconnectors 38 includes a proximal end 44, a distal end 46, and anexterior surface 48 extending from the proximal end 44 to the distal end46. The distal end 46 is nearest the terminal pin receiving port 36.

The plurality of connecting wires 42 may electrically connect theexterior surface 48 of each of the first electrical connectors 38, andan external surface of each of the second electrical connectors 40, tooperational circuitry 20 by way of the electrical feedthrough 34.Considering FIGS. 1 and 2 together, when the proximal end 22 of theelectrical lead 14 is coupled to the lead connector block 18, the firstterminal contact 26 may be in electrical contact with the firstelectrical connector 38, and the second terminal contact 28 may be inelectrical contact with the second terminal contact 40. So coupled, theoperational circuitry 20 within case 16 may be electrically connected tothe first terminal contact 26 and the second terminal contact 28 of theelectrical lead 14.

FIGS. 3A and 3B are a proximal end view and a cross-sectional view,respectively, of the electrical connector 38 shown above in reference toFIG. 2. Considering FIGS. 3A and 3B together, the electrical connector38 may include a housing 50 and a plurality of spring contacts 52. Thehousing 50 may include the exterior surface 48 (which is also theexterior surface 48 of the electrical connector 38 as noted above) andan interior surface 54. The interior surface 54 may be in the form of ahollow cylinder having an axis A. The spring contacts 52 may projectfrom the interior surface 54 of housing 50 and toward the proximal end44. As shown in FIGS. 3A and 3B, the spring contacts 52 may be containedwithin the housing 50. In other embodiments, the spring contacts 52 mayproject beyond the proximal end 44 and, thus, be partially containedwithin the housing 50.

Each of the spring contacts 52 illustrated in FIGS. 3A and 3B have alength L extending from the housing 50 to a tip 56 of the spring contact52. Each of the spring contacts 52 has an average cross-sectional aspectratio along its length L. The cross-sectional aspect ratio at any pointalong the length L is the ratio of a largest cross-sectional dimensionto a smallest cross-sectional dimension in a plane intersecting thespring contact 52 at the point along length L, the plane beingperpendicular to axis A (the axis A being a central axis of the housing50). In some embodiments, the cross-sectional shape at most points alongthe length L may be approximately circular. A circular cross-section hasa cross-sectional aspect ratio of 1 and is the lowest possiblecross-sectional ratio. Other embodiments may have other cross-sectionalshapes such as, for example, elliptical, rectangular, or triangular. Insome embodiments, the average cross-sectional aspect ratio along thelength L of the spring contacts 52 may be about 1. In other embodiments,the average cross-sectional aspect ratio along the length L of thespring contacts 52 may be about 3. In some embodiments, the averagecross-sectional aspect ratio along the length L of the spring contacts52 may be between 1 and 3.

FIGS. 3A and 3B illustrate the electrical connector 38 in a condition inwhich the electrical lead 14 is not coupled to the lead connector block18. That is, the spring contacts 52 are in a relaxed state and areextending at least partially toward the axis A of the housing 50. Incontrast, FIGS. 4A and 4B are a proximal end view, and a cross-sectionalview, respectively, of the electrical connector 38 illustrating acondition in which the electrical lead 14 is coupled to the leadconnector block 18 forming an electrical connection between theelectrical connector 38 and the first terminal contact 26 of electricallead 14. In a relaxed state, a portion of each of the spring contacts 52along the length L extends toward the axis A such that a radial distancefrom the axis A to the portion of the spring contact 52 is less than aradius of the electrical lead 14 at the first terminal contact 26. Thisensures that when the electrical lead 14 is coupled to the leadconnector block 18, the first terminal contact 26 pushes against theplurality of spring contacts 52, as shown in FIGS. 4A and 4B. Due to theresilient nature of the spring contacts 52, they move radially outwardfrom the axis A, producing a normal force between the spring contacts 52and the first terminal contact 26. In this way, embodiments of theelectrical connector 38 form an electrical connection between theelectrical lead 14 and the IMD 12.

Embodiments of the electrical connector 38 in which the spring contacts52 have an average cross-sectional aspect ratio along their length Lthat is relatively low, such as 1, or 3, or between about 1 and about 3,may be more resilient to repeated coupling and decoupling between theelectrical lead 14 and the lead connector block 18 compared with flat,or leaf, spring contacts which may have higher average cross-sectionalaspect ratios along their lengths. The lower average cross-sectionalaspect ratio for embodiments of the electrical connector 38 may make itless likely that any of the spring contacts 52 may be permanentlydeformed by being physical overstressed. Being more resilient torepeated coupling and decoupling may mean that in such embodiments ofthe electrical connector 38, the spring contacts 52 are able to providea more consistent normal force between the spring contacts 52 and thefirst terminal contact 26.

Embodiments of the electrical connector 38 may include many more of thespring contacts 52 than would be possible for flat, or leaf, spring dueto the relatively low average cross-sectional aspect ratio along theirlength L of the spring contacts 52. In some embodiments, the electricalconnector 38 may include at least twenty spring contacts 52. In otherembodiments, the electrical connector 38 may include at leasttwenty-five spring contacts 52. A greater number of spring contacts 52may provide a lower resistance connection between the electricalconnector 38 and the first terminal contact 26.

Embodiments of the electrical connector 38, including the housing 50 andthe plurality of spring contacts 52 may be integrally formed such thatthe electrical connector 38 is a unitary structure. Such embodiments ofthe electrical connector 38 may be formed by an additive manufacturingprocess, such as, a powder bed fusion process as described below inreference to FIG. 8, or by other additive manufacturing processes, forexample, directed energy deposition (e.g. laser engineered net shaping(LENS)). Embodiments in which the electrical connector 38 is integrallyformed may have significant advantages over electrical connectors inwhich a housing and spring contacts are separate components. Oneadvantage may be in the reduction in assembly complexity and cost byhaving a single component electrical connector instead of an electricalconnector having two or more components. Another advantage is theremoval of a physical and electrical contact interface between thehousing and the spring contacts. Electrical connectors in which thehousing and spring contacts are separate components may include aphysical interface between the two components across which an electricalconnection must be maintained. Such an interface may add a resistance tothe electrical connection between the electrical lead 14 and theoperational circuitry 20 due to native oxide layers at the contactingmetal surfaces and the imperfectly matching surface topography presentedby the contacting metal surface, which may prevent complete physical andelectrical contact between the surfaces. Such native oxide layers andcontact surface topography may be random and uncontrolled in theireffect, leading not only a higher electrical connector resistance, but amore variable electrical connector resistance as well. Embodiments ofthe electrical connector 38 having a unitary structure do not have aphysical interface between the housing 50 and the spring contacts 52.Thus, such embodiments of the electrical connector 38 may advantageouslypresent a lower electrical connector resistance and a more consistentconnection between the electrical lead 14 and the IMD 12.

The unitary structure of the housing 50 and the plurality of springcontacts 52 may be made of a conductive metal such as, for example,nickel/cobalt/chromium alloys, stainless steels (e.g., 316L),platinum/iridium alloys, silver, or titanium, or a combination thereof.

In the embodiments of the electrical connector 38 described above andshown in FIGS. 4A, and 4B, each of the spring contacts 52 may becoplanar with the axis A, that is, a single plane may contain both acenter of each spring contact 52 along its length L, and the axis A. Insuch embodiments, an intersection between each of the spring contacts 52and the first terminal contact 26 may be a line parallel to the axis A.In other embodiments, the spring contacts may be canted such that anintersection between each of the spring contacts and the first terminalcontact 26 may be a line that is not parallel to the axis of thehousing. In other embodiments, the spring contacts may be spiraled suchthat an intersection between each of the spring contacts and the firstterminal contact 26 may be a curve. Thus, there is no spiral or cantshown with respect to the spring contacts 52 of the electrical connector38. Embodiments having a spiral or cant with respect to the springcontacts are described below.

FIGS. 5A and 5B are a distal end view and a cross-sectional view,respectively, of another electrical connector having spring contactsthat are spiraled, in accordance with embodiments of the presentinvention. Together, FIGS. 5A and 5B show an electrical connector 138including a proximal end 144, a distal end 146, a housing 150, and aplurality of spring contacts 152. In FIG. 5A, a portion of the housing150 is illustrated in outline so that the details of the spring contacts152 may be more easily shown. The housing 150 may include an exteriorsurface 148 and the interior surface 154. The interior surface 154 maybe in the form of a hollow cylinder having an axis A. The springcontacts 152 may project from the interior surface 154 of housing 150and toward the proximal end 144 to a tip 156. As shown in FIGS. 5A and5B, the spring contacts 152 may be spiraled at least partially aroundthe axis A of housing 150. The spiraling of the spring contacts 152relative to the axis A may result in a longer physical contact regionbetween each of the spring contacts 152 and the first terminal contact26 inserted into the electrical connector 138. Also, the spiraling ofthe spring contacts 152 may result in a larger deflection range overwhich the normal pressure applied by the spring contacts 152 isconsistent. This feature might produce a more consistent contactresistance between the spring contacts 152 and the first terminalcontact 26 in cases where a diameter of the first terminal contact 26varies between the electrical leads 14.

As further shown in FIGS. 5A, and 5B, in some embodiments of theelectrical connector 138, the housing 150 may further include a proximalend shoulder 160 and/or a distal end shoulder 162. The proximal endshoulder 160 may project radially inward toward the axis A at theproximal end 144. The distal shoulder 162 may project radially inwardtoward the axis A at the distal end 146. The proximal end shoulder 160and the distal end shoulder 162 may help align the electrical lead 14within the electrical connector 138 and may prevent overstressing thespring contacts 152. As with the spring contacts 52 described above forelectrical connector 38, the spring contacts 152 may have an averagecross-sectional aspect ratio along their length that is relatively low,such as 1 or 3, or between about 1 and about 3, and are thus moreresistant to damage from being overstressed. The electrical connector138 with the spring contacts 152 having an average cross-sectionalaspect ratio along their length L that is relatively low, in combinationwith the proximal end shoulder 160 and/or the distal end shoulder 162,may be advantageously resistant to damage to the spring contacts 152.

Embodiments of the electrical connector 138, including the housing 150and the plurality of spring contacts 152 may be integrally formed suchthat the electrical connector 138 is a unitary structure. Suchembodiments of the electrical connector 138 may be formed by an additivemanufacturing process, such as, a powder bed fusion process as describedbelow in reference to FIG. 8, or by another additive manufacturingprocess.

FIGS. 6A and 6B are a distal end view, and a cross-sectional view,respectively, of another electrical connector having spring contactsthat are canted, in accordance with embodiments of the presentinvention. Together, FIGS. 6A and 6B show an electrical connector 238including a proximal end 244, a distal end 246, a housing 250, and aplurality of spring contacts 252. The housing 250 may include anexterior surface 248, and the interior surface 254. The interior surface254 may be in the form of a hollow cylinder having an axis A. The springcontacts 252 may project from the interior surface 254 of housing 250and toward the proximal end 244 to a tip 256. As shown in FIGS. 6A and6B, the spring contacts 252 may be blades that are canted. The cantingof the spring contacts 252 may result in a larger deflection range overwhich the normal pressure applied by the spring contacts 252 isconsistent. This feature might produce a more consistent contactresistance between the spring contacts 252 and the first terminalcontact 26 in cases where a diameter of the first terminal contact 26varies between the electrical leads 14.

In the embodiment of FIGS. 6A and 6B, the spring contacts 252 areillustrated as flat blades that are canted. However, it is understoodthat embodiments may also include curved blades that are canted. Suchblades may offer increased contact area between the electrical connector238 and the first terminal contact 26.

As further shown in FIGS. 6A and 6B, in some embodiments of theelectrical connector 238, the housing 250 may further include a proximalend shoulder 260 and/or a distal end shoulder 262. The proximal endshoulder 260 may project radially inward toward the axis A between thetip 256 and the proximal end 244. The distal shoulder 262 may projectradially inward toward the axis A at the distal end 246. The proximalend shoulder 260 and the distal end shoulder 262 may help align theelectrical lead 14 within the electrical connector 238 and may preventoverstressing the spring contacts 252.

Embodiments of the electrical connector 238, including the housing 250and the plurality of spring contacts 252 may be integrally formed suchthat the electrical connector 238 is a unitary structure. Suchembodiments of the electrical connector 238 may be formed by an additivemanufacturing process, such as, a powder bed fusion process as describedbelow in reference to FIG. 8, or by another additive manufacturingprocess.

FIGS. 7A and 7B are a distal end view, and a cross-sectional view,respectively, of another electrical connector having spring contactsthat are spiraled, in accordance with embodiments of the presentinvention. Together, FIGS. 7A and 7B show an electrical connector 338including a proximal end 344, a distal end 346, a housing 350, and aplurality of spring contacts 352. The housing 350 may be in the form ofa two-piece hollow cylinder having an axis A and include a distalportion 364 and a proximal portion 366. The distal portion 364 isaxially apart from the proximal portion 366. The housing 350 may alsoinclude an exterior surface 348, an interior surface 354, a proximal endshoulder 360 and/or a distal end shoulder 362. The proximal end shoulder360 may project radially inward toward the axis A from the proximalportion 366. The distal shoulder 362 may project radially inward towardthe axis A from the distal portion 364 at the distal end 346. Theproximal end shoulder 360 and the distal end shoulder 362 may help alignthe electrical lead 14 within the electrical connector 338.

As shown in FIGS. 7A and 7B, the spring contacts 352 may project fromthe interior surface 354 of the distal portion 364 and toward theproximal end 344 to connect with the proximal portion 366 at theproximal end shoulder 360. That is, the distal portion 364 and theproximal portion 366 may be connected to each other by the springcontacts 352. In some embodiments, spring contacts 352 may spiraled. Thespiraling of the spring contacts 352 relative to the axis A may resultin a longer physical contact region between each of the spring contacts352 and the first terminal contact 26 inserted into the electricalconnector 338. Also, the spiraling of the spring contacts 352 may resultin a larger deflection range over which the normal pressure applied bythe spring contacts 352 is consistent. This feature might produce a moreconsistent contact resistance between the spring contacts 352 and thefirst terminal contact 26 in cases where a diameter of the firstterminal contact 26 varies between the electrical leads 14.

As with the spring contacts 52 described above for electrical connector38, the spring contacts 352 may have an average cross-sectional aspectratio along their length that is relatively low, such as 1, or 3, orbetween about 1 and about 3, and are thus more resistant to damage frombeing overstressed. The electrical connector 338 with the springcontacts 352 having an average cross-sectional aspect ratio along theirlength L that is relatively low, in combination with the proximal endshoulder 360 and/or the distal end shoulder 362, may be advantageouslyresistant to damage to the spring contacts 352. In addition, byseparating the housing 350 into two portions physically apart, thedistal portion 364 and the proximal portion 366, and connected to eachother only by the spring contacts 352, the spring contacts 352 are ableto flex, while both ends of the spring contacts 352 are physicallysupported. This arrangement may provide additional protection for thespring contacts 352.

Embodiments of the electrical connector 338, including the housing 350and the plurality of spring contacts 352, may be integrally formed suchthat the electrical connector 338 is a unitary structure. Suchembodiments of the electrical connector 338 may be formed by an additivemanufacturing process, such as, a powder bed fusion process, asdescribed below in reference to FIG. 8, or by another additivemanufacturing process.

FIG. 8 is a schematic view of a powder bed fusion system for additivelymanufacturing electrical connectors, such as the electrical connector38, the electrical connector 138, the electrical connector 238, and theelectrical connector 338 in accordance with embodiments of the presentinvention. FIG. 8 illustrates an additive manufacturing system 400including a controller 402, an energy beam source 404, a working surface406, a moveable platform 408, a coating device 410, and a dispenser 412.The controller 402 may be a computing/controlling device controlling atleast the energy beam source 404, the moveable platform 408, the coatingdevice 410, and the dispenser 412. The energy beam source 404 may be anysystem able to generate an energy beam 414 and direct it to any positionon the moveable platform 408. The energy beam 414 may be, for example, alaser beam or an electron beam. The moveable platform 408 may movevertically relative to working surface 406. The coating device 410 maymove horizontally back and forth across the working surface 406 and themoveable platform 408 to sweep powder 416 dispensed from the dispenser412 onto the moveable platform 408.

In operation, the controller 402 may direct the moveable platform 408 tobe recessed from the working surface 406 by an amount equal to a desiredlayer thickness. The controller 402 may then direct the dispenser 412 todispense a desired quantity of the powder 416 onto the working surface406. The controller 402 may then direct the coating device 410 to sweepback and forth across the moveable platform 408 to deposit the powder416 on to the moveable platform 408 at the desired layer thickness. Thecontroller 402 may then direct the energy beam source 404 to generatethe energy beam 414 at predetermined positions across the moveableplatform 408 to sinter or fuse together the powder 416 at thepredetermined positions. The predetermined positions across the moveableplatform 408 correspond to the structure of a layer of the electricalconnector 38. The controller 402 may then direct the moveable platform408 to move down the desired thickness of the next layer and theprevious steps may be repeated to produce another desired layer of theelectrical connector 38. The preceding steps may be repeated multipletimes as necessary as part of a method for manufacturing the electricalconnector 38 in a layer-by-layer fashion in which the electricalconnector 38 is integrally formed as a unitary structure. It isunderstood that the electrical connector 38 may also represent any ofthe electrical connector 138, the electrical connector 238, or theelectrical connector 338 described above, or any other embodiment inaccordance with the present invention. As shown in FIG. 8, a pluralityof the electrical connectors 38 may be produced at the same time. It isalso understood that a combination of various electrical connectorsembodying the present invention may be manufactured together asdescribed above.

In some embodiments, the powder 416 used to make the electricalconnector 38 may be a metal powder having an average particle size ofless than about 10 micrometers. In some embodiments, the powder 416 maybe a metal powder having an average particle sized of about 5micrometers. In other embodiments, the powder 416 may be a metal powerhaving an average particle size less than 5 micrometers. Averageparticle size may be determined by a laser diffraction based particlesize analyzer, for example, a Malvern® Mastersizer 2000™. Employingmetal powders having average particle sizes of about 5 micrometers, orless than about 10 micrometers and in which the energy beam 414 is alaser beam may be referred to as micro-laser sintering. Dimensional andmorphological control of the additive manufacturing of the electricalconnector 38 may be enhanced with micro-laser sintering. The powder 416may also be, for example, a stainless steel (e.g., 316L), aplatinum/iridium alloy, silver, or titanium. The powder 416 may also be,for example, a nickel/cobalt/chromium alloy including about 34 to 36 wt.% nickel, about 19 to 21 wt. % chromium, about 9 to 11 wt. % molybdenum,and about 32 to 38 wt. % cobalt. In some embodiments, the powder 416 mayconsist essentially of 34 to 36 wt. % nickel, 19 to 21 wt. % chromium, 9to 11 wt. ° % molybdenum, and 32 to 38 wt. % cobalt.

Additive manufacturing of a metal part, such as the electrical connector38 may result in a surface finish that is, in some locations, moretextured than desired. In some embodiments the method manufacturing theelectrical connector 38 may further include finishing at least a portionof any surfaces of the electrical connector 38. For example, it may bebeneficial to electrochemically polish surfaces of the plurality ofspring contacts 52 and the interior surface 54, but not the exteriorsurface 48. Additionally or alternatively, other finishing processes maybe employed including mechanical polishing, electro plasma polishing,glazing, wet blasting, grit blasting, and wire electrical dischargemachining. In some embodiments, passivating techniques may also beemployed to remove stray impurities from the surface, such as iron.

Although the housing 50 shown in FIGS. 2, 3A, 3B, 4A and 4B as afeatureless structure, it is understood that features may be added. Forexample, a structure may be added to the external surface 48 to enhancean electrical connection between the electrical connector 38 and theconnection wire 42. In another example, portions of the housing 50 maybe omitted to the extent that the conductivity and strength ofelectrical connector 38 remains sufficient for its intended purpose.Such examples may include a series of holes between the exterior surface48 and the interior surface 54. Reducing the metal volume of theelectrical connector 38 in this fashion may reduce the time required toadditively manufacture the electrical connector 38.

For the sake of brevity, embodiments have been described above inreference to the electrical connector 38 (or 138, 238, or 338)configured to form an electrical connection with the first terminalcontact 26 of the electrical lead 14. However, it is understood that theelectrical connector 40 configured to form an electrical connection withthe second terminal contact 28 may also embody the present invention.

Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentinvention. For example, while the embodiments described above refer toparticular features, the scope of this invention also includesembodiments having different combinations of features and embodimentsthat do not include all of the described features. Accordingly, thescope of the present invention is intended to embrace all suchalternatives, modifications, and variations as fall within the scope ofthe claims, together with all equivalents thereof.

We claim:
 1. An electrical connector for detachably connecting anelectrical lead to an implantable medical device, the connectorcomprising: a conductive housing extending from a proximal end to adistal end, the conductive housing having an interior surface forming ahollow cylinder; and a plurality of spring contacts projecting from theinterior surface of the conductive housing and toward the proximal end,wherein the plurality of spring contacts is at least partially containedwithin the conductive housing and configured to form an electricalconnection to an electrical lead inserted within the conductive housing;wherein the conductive housing and the plurality of spring contacts areintegrally formed by an additive manufacturing process such that theelectrical connector is a unitary structure.
 2. The electrical connectorof claim 1, wherein the each spring contact of the plurality of springcontacts has a length extending from the conductive housing to a tip ofthe spring contact, and an average cross-sectional aspect ratio alongits length, wherein the average cross-sectional aspect ratio is about 1to about
 3. 3. The electrical connector of claim 2, wherein the averagecross-sectional aspect ratio is about
 1. 4. The electrical connector ofclaim 1, wherein the additive manufacturing process is a powder bedfusion process employing a metal powder, wherein the metal powder is analloy including about 34 to 36 wt. % nickel, about 19 to 21 wt. %chromium, about 9 to 11 wt. % molybdenum, and about 32 to 38 wt. %cobalt.
 5. The electrical connector of claim 1, wherein each springcontact of the plurality of spring contacts has a length extending fromthe conductive housing to a tip of the spring contact, and has anelliptical cross-sectional shape along at least a portion of its length.6. The electrical connector of claim 1, wherein each spring contact ofthe plurality of spring contacts has a length extending from theconductive housing to a tip of the spring contact, and has a triangularcross-sectional shape along at least a portion of its length.
 7. Theelectrical connector of claim 1, wherein the plurality of springcontacts includes at least twenty spring contacts.
 8. The electricalconnector of claim 1, wherein the conductive housing further includes: adistal portion adjacent to the distal end; and a proximal portionadjacent to the proximal end and spaced apart from the distal portion;wherein the plurality of spring contacts projects from the interiorsurface of the distal portion of the conductive housing and toward theproximal end, and the proximal portion is connected to the distalportion by the plurality of spring contacts.
 9. The electrical connectorof claim 1, wherein each spring contact of the plurality of springcontacts is canted or spirals at least partially around an axis of theconductive housing.
 10. A method for manufacturing an electricalconnector for detachably connecting an electrical lead to an implantablemedical device, the method comprising: performing an additivemanufacturing process to form an electrical connector, the electricalconnector including a conductive housing having an interior surfaceextending from a proximal end to a distal end forming a hollow cylinderand a plurality of spring contacts projecting from the interior surfaceof the conductive housing and toward the proximal end, the plurality ofspring contacts at least partially contained within the conductivehousing and configured to form an electrical connection to an electricallead inserted within the conductive housing wherein the conductivehousing and the plurality of spring contacts are integrally formed bythe additive manufacturing process such that the electrical connector isa unitary structure.
 11. The method of claim 10, further comprisingfinishing at least a portion of surface of the electrical connector. 12.The method of claim 11, wherein finishing includes at least one ofelectrochemical polishing, mechanical polishing, electro plasmapolishing, glazing, wet blasting, grit blasting, wire electricaldischarge machining, and passivating techniques.
 13. The method of claim10, wherein the additive manufacturing process is a powder bed fusionprocess.
 14. The method of claim 13, wherein the powder bed fusionprocess is a micro laser sintering process employing a metal powderhaving an average particle size of less than about 10 micrometers. 15.The method of claim 14, wherein the metal powder has an average particlesize of about 5 micrometers.
 16. An implantable medical devicecomprising: a case including: operational circuitry for providingtherapy; and an electrical feedthrough electrically connected to thecircuit; and a lead connector block attached to the housing at theelectrical feedthrough, the lead connector block configured to receiveat least one terminal pin of an electrical lead, the terminal pinincluding at least one terminal pin contact, the lead connector blockincluding: an electrical connector electrically connected to theelectrical feedthrough for detachably connecting the operationalcircuitry to the electrical lead, the connector including: a conductivehousing extending from a proximal end to a distal end, the conductivehousing having an interior surface forming a hollow cylinder; and aplurality of spring contacts projecting from the interior surface of theconductive housing and toward the proximal end, wherein the plurality ofspring contacts is at least partially contained within the conductivehousing and configured to form the electrical connection to the terminalpin contact of the electrical lead inserted within the conductivehousing; wherein the conductive housing and the plurality of springcontacts are integrally formed by an additive manufacturing process suchthat the electrical connector is a unitary structure.
 17. The device ofclaim 16, wherein each spring contact of the plurality of springcontacts has a length extending from the conductive housing to a tip ofthe spring contact, and an average cross-sectional aspect ratio alongits length, wherein the average cross-sectional aspect ratio is about 1to about
 3. 18. The device of claim 16, wherein the additivemanufacturing process is a powder bed fusion process employing a metalpowder, wherein the metal powder is an alloy including about 34 to 36wt. % nickel, about 19 to 21 wt. % chromium, about 9 to 11 wt. %molybdenum, and about 32 to 38 wt. % cobalt.
 19. The device of claim 16,wherein each spring contact of the plurality of spring contacts has alength extending from the conductive housing to a tip of the springcontact, and has an elliptical cross-sectional shape along at least aportion of its length.
 20. The device of claim 16, wherein the pluralityof spring contacts includes at least twenty spring contacts.